Safety related and other critical devices usually have several voltage references, namely two, three or more voltage references. Of particular importance is the tolerance of such devices to failures which may affect any single one of these voltage references, like loss of the connection to ground by a ground node (called “ground loss”), such as by a ground pad of an integrated circuit to the external ground e.g. due to a disconnecting bond-wire, or to another voltage reference node.
Some or all of the available voltage reference nodes of an electronic device may be connected such that the voltage reference nodes are all at the same electrical potential, even in case of a loss of the connection to the reference voltage source for a specific node. For example. European patent application publication EP-0519156 A discloses a protection of an output driver with an extra ground circuit to prevent the loss of connection between a reference node of the driver and ground of the driver. In case of a loss of connection, an additional path between the reference node and the output terminal of the driver is enabled. The additional path provides the voltage at the output terminal to the reference node and thus avoids that the driver becomes dysfunctional.